In the case of such longitudinal guide rails the several locking teeth never engage together into notched openings, to the contrary in most blocking conditions at least on blocking finger rests on a notch. The blocking fingers do neither all engage in full depth into a notched opening, in the contrary, typically at least one locking tooth engages only partially into a notched opening, here it lies in most cases against a sloping side at the edge of the notched opening. For the locking only two locking fingers are needed, of which one takes charge of the locking into one sliding direction and the other of the locking into the other sliding direction. The device for locking has in most cases three to four blocking fingers.
So, in the case of a typical locking position, there generally is at least one misnotched blocking finger, typically at least one blocking finger, which only partially engages and finally at least one blocking finger, which engages fully.
Such devices for locking are especially suitable for longitudinal guide rails, but they can also be used for other manually operated locking devices on adjustable motor vehicle seats, for example for setting the angle of a rest hinged mounting or for the height adjustment of the front edge of a seat.
The unlocking hatch is constructed as delayed action switch. In the cases of an unlocking process it initially works together with at least one fully engaged blocking finger, and pulls it up. In the case of a continuation of the unlocking movement its carriers get in contact with at least the one only partially engaged blocking finger, which also is lifted up. Finally, the unlocking hatch takes, with the associated carrier, in the case of a continuation of the unlocking movement at least one blocking finger along, which is misnotched. In the case of the same being lifted up, all existing blocking fingers are picked up from the unlocking hatch. The lift movement must be carried out to such an extent, that the rails can be freely adjusted in opposition.
In the case of the described practical operation the operator feels a graded operator force. Initially only the one, fully engaged blocking finger must be lifted up via the unlocking hatch, in case of a continuation of the unlocking movement the operator force increases, if at least on partially engaged blocking finger is pulled up, finally the maximum operational force is existent, when all blocking fingers are pulled by the unlocking hatch. A user then notices during the unlocking movement of the blocking fingers a stage rising force, which is conditional of the retaining spring of the individual blocking fingers.
The above-mentioned unexamined German application offers already a solution for the fact that for the user power stages, which are as small as possible, occur during the release movement. Alternating short or longer notched openings are arranged consecutively in the notching rail.
Disturbing is the relative large construction height of the device for locking at the known longitudinal guide rails. Starting from this, it is the task of the invention to create a device for locking, especially for a longitudinal guide rail, which on the one hand allows a small construction height in the longitudinal direction of the blocking fingers and which, on the other hand, influences the operational force during the release process through suitable measures in such a way, that the described power stages, which occur during the release process, are hardly noticeable for the user.